Copolymers of unsaturated sulfonic acids and polyunsaturated compounds



Patented Oct. 24, 1950 COPOLYMERS OF UNSATURATED SULFONIC ACIDS AND POLYUNSATURATED COM- POUNDS James R. Dudley, Darien, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application March 18, 1948, Serial No. 15,726

3 Claims.

This invention relates to cation exchange materials, a method of manufacturing cation exchange materials, and the use of cation exchange materials for the removal of cations from, or the exchange of cations in, liquid media. More particularly, the invention relates to new granular, water-insoluble, synthetic cation exchange resins active for the removal of cations from solution.

It is an object of the present invention to provide a new synthetic cation exchange resin active for the removal of cations from solution.

It is another object of the present invention to provide a process for the preparation of new synthetic cation exchange resins active for the removal of cations from solution.

A further object of the present invention is a process for the purification of liquids by means of new granular, water-insoluble, synthetic cation exchange resins active for the removal of cations from solution.

The above and other objects are attained by the preparation of a copolymer of a polymerizable organic sulfonic acid containing at least one CH2=C group, or a substance hydrolyzable thereto, and a polymerizable poly-unsaturated organic material, and application of said copolymer in granular form to the purification of liquids and more particularly, of aqueous solutions.

In the past, ethylenesulfonic acid has been polymerized alone, and it has been copolymerized with other substances such as methyl alphachloroacrylate, chloroprene, and the like. The resulting products are linear polymers which are not useful as cation exchange resins because of their high water solubility.

The invention will be described in greater detail in conjunction with the following specific examples in which proportions are given in parts by weight. The examples are merely illustrative, and it is not intended that the scope of the invention be restricted to the details therein set forth.

Example 1 14.5 parts of ethylenesulfonic acid (0.13 mol.)

14.5 parts of N,N'-methylenediacrylamide (0.09

mol.)

29 parts of water 0.2 part of potassium persulfate in 5 parts of water The N,N'-methylenediacrylamide is dissolved in the ethylenesulfonic acid by heating to 110 C. with agitation. The solution is then cooled to 40 C. and the water is added. The potassium persulfate solution is added to the diluted, cooled ethylenesulfonic acid solution, whereupon practically instantaneous formation of an opaque gel is accompanied by a temperature rise to '70-80 C. The gel is broken up, allowed to dry at 30 C. for three days, and then dried for four hours, at 100 C.

The resin obtained is activated with hydrochloric acid and then exhausted to sodium bicarbonate solution. It has a density of 20.8 lbs. per cubic foot, and a capacity for the removal of cations from solution equivalent to 3.5 kilograms of CELCOs per cubic foot of resin.

Example 2 12 parts of ethylenesulfonic acid (0.11 mol.)

6 parts of N,N'-methylenediacrylamide (0.04

mol.)

10 parts of sodium hydroxide in 10 parts of water 10 parts of dioxane (commercial product containing peroxides) The N,N'-methylenediacrylamide is dissolved in the ethylenesulfonic acid by heating, and the sodium hydroxide solution is added. While maintaining the temperature sufficiently high to keep the solid material dissolved, the dioxane is added. The gel which forms almost immediately is dried for 20 hours at 0., and upon activation and exhaustion as described in Example 1, the resin is found to have a density of 8.3 lbs. per cubic foot and a capacity for the removal of cations from solution equivalent to 10.1 kilograins of CaCOz per cubic foot of resin.

Example 3 24 parts of ethylenesulfonic acid (0.22 mol.)

6 parts of N,N'-methylenediacrylamide mol.)

17.2 parts of sodium hydroxide in 17.2 parts of Water 20 parts of water 6 parts of dioxane (commercial product containing peroxides) found to have a density of 4.8 lbs. per cubic foot and a capacity for the removal of cations from solution equivalent to 8.0 kilograins of CaCOa per cubic foot of resin.

The N,N'-methylenediacrylamide used in the preceding examples may be prepared in accordance with the disclosure of the copending application of Lennart A. Lundberg, Serial No. 707,040 filed October 31, 1946, now Patent No, 2,475,846 dated July 12, 1949, as follows:

199 parts of acrylamide (2.8 mols.)

113 parts of formaldehyde (1.4 mols.)

2 parts of cupric acetate 150 parts of water 47 parts of concentrated hydrochloric acid (37%) To a well agitated mixture of the acrylamide, formaldehyde, cupric acetate and water is added the hydrochloric acid. An exothermic reaction occurs, and after it has subsided the mixture is heated for /2 hour. A white crystalline solid separates on cooling and is recovered by filtration. This material, which represents a 50% yield of N,N'-methylenediacrylamide based on the theoretical, is recrystallized from ethanol. The pure product is found to have a melting point of 185- 186 C. and the following analysis:

Calculated for Found THmOaN:

Per cent Per cent Carbon 54.53 54. 61 dr 6 a 3' H en .5

y g B. 42 Nitrogen l 18. 1B 18. 09 18.15

wherein R is hydrogen, methyl, or a halogen, X is an alkyl group containing from 1 to 8 carbon atoms, a halogen atom, or a hydroxyl group, and n is zero or a whole number from 1 to 3. For example, I may use:

SOIH

0-, m-, or p-styrene sulfcnic acids 0-, m-, or p-isopropenylbenzene sultonlc acids C=CH2 0-, m-, or p-alpha-chlorostyrene suli'onic acids 0-, m-, or p-alpha-bromostyreue sultonic acids BOaH C=CH8 i,

2-vinyl-3-chlorobenzenesultcnlc acid CH=CH1 2-vinyl-4-bromobeuzenesultonic acid 2-vinyl-5-fluorobcnzenesultonic acid CH=CH3 2-viny1-6-chlorobenzenesultonic acid 2-1:romo-3-vinylbenzenesulfonic acid CH=CH| 3-vlnyl-4-chlorobenzcnesultonlc acid 01 CH=CH1 3-vluyl-5-bromobenzenesulfonic acid 3Fchloro+vinylbenzenesulfonlc acid GH=0Ha matic sulfonic acids may also be used as, for example:

l-hydroxy-4-sulfo-6-vinylnaphthalene Also suitable for use in the preparation of my new copolymers are those unsaturated aromatic sulfonic acids in which the CH2=C group is attached not directly to a nuclear carbon, as in the ov i d ex ples. but to an aliphatic carbon. Thus, allylbenzenesulfonic acids, methalLvlbenzenesulfonic acids, and haloallylbenzenesulfonic acids as, for example,

2-ailylbenzenesulfonic acid CHa- CH: C H:

3-beta-methallylbenzenesulfonic acid CH|C=CH:

4-beta-broma1lylbenzenesulfonic acid ('JHr-C=CH,

may be used.

Aromatic sulfonic acids in which the sulfonic acid group is attached not to a nuclear carbon but to an aliphatic carbon atom are also suitable for use according to the present invention. Thus,

acids having the general formula R =CH| Y (801B) II in which x may be a halogen atom, a hydroxyl group, or an alkyl group having 1 to 8 carbon atoms, R is hydrogen or methyl or a halogen atom, Y is a divalent aliphatic, saturated or unsaturated, hydrocarbon radical having from 1 to 4 carbon atoms, m is 1 or 2, and n is zero or a whole number from 1 to 3. Some examples of such acids are:

0-, m-, or p-vinylphenylmethanesulfonic acids CHa-SOzH CH=CH3 0-, m-, or p-vinylphenylethanesulfonic acids CHQCHISOaH CH=CH1 0-, m-, or p-isopropenylphenyl-n-butanesultonic acids (CHmS O;H

0-, m-, or p-alpha-chlorovinylphenyi-n-propanesulfonic acids ihs sH C=CH2 2-vinyl-3-chlorophenylmethanesulfonic acid CH=CH:

2-vinyl-4-chlorophenylethanesulfonic acid CH=CH8 HsCHiS 0 H 2-vinyl-5-bromophenyI-n-butanesulfonic acid ((IJHI) 4S 0 :H

2-viny1-3-methylphenylmethanesulfonic acid -CH=CH| E H B 0 1H 2-vinyl-4-ethylphenyl-n-propanesulfonic acid CH=CH1 2-isopropenyl-B-n-octylpbenylethanesulfonic acid sC (HaC) H|CH2SO3H 3-methyl-4-alpha-chlorovinylphenylmethanesulfonic acid CHI 11180111 3-vlnyl-4-hydroxyphenylmethanesnlfonlc acid gor es, H23 03H 2-vinyl-3,4,5-trihydroxyphenylethanesulfonic acid HO OH CH=CH1 2-isopropenyl-4-hydroxrim-c1310rophenylmethanesulfonic 2-vlnyl-4-etl1yl-6-chl0rophenyl-n-propanesulfonic acid (CH2):SO3H 1-[2-vinylphenyll-n-butanedisulfonic acid-2,4

1- [4-vinylphenyl 1 -ethanesulfonic acid-1 C H: C Hz (IH- CH: SOsH 4-[3-vinylphenyl]-2 butenesulfonic acid-2 CH=CHI Sulfonic acids containin sulfonic acid groups attached both to nuclear and aliphatic carbon atoms may also be used as, for example, l-sulfo- 3-vinylpheny1methanesulfonic acid.

CH=CH2 CHESORH Aliphatic sulfonic acids suitable for use in the present invention include those represented by the general formula in which X may be hydrogen or a group such as halogen, carboxyl, sulfo, cyano, carbamyl, nitro, aryl, i. e., phenyl, tolyl, xylyl, biphenylyi, naphthyl, etc., saturated or unsaturated aliphatic hydrocarbon radicals having from 1 to 5 carbon atoms, i. e., methyl, ethyl, isopropyl, n-butyl, isobutyl, tert.butyl, n-amyl, isoamyl, tertamyl, alyl, 2-butenyl (crotyl) etc. and the radicals -COOR, --COR, CONR.2, -OR, and RCOO- in which R may be any organic hydrocarbon groupaliphatic or aromatic, saturated or unsaturated-but is preferably an alkyl group of from 1 to 5 carbon atoms. Y is a divalent aliphatic saturated or unsaturated hydrocarbon radical of from 1 to 4 carbon atoms, and n is 1 or 2. Thus, I may use, in addition to ethylenesulfonic acid itself,

l-bromoethylenesulfonic acid CH=CSO H tr l.-cyanoethylenesulfonlc acid CH|=CSOaH 1-carbamyiethylcnesultonic acid OHI=CS 03H ONE:

l-nitroethyienesultonic acid l-phenylethylenesulfonic acid CH=C-SO:H

1-isopropyletbylenesulfonic acid CH:=CS0|H H 1 91 l-allylethylenesultonic acid CH5=C-SOaH 1-carbethoxyethyienesultonic acid CH|=C-S0|H OOCIHI 1-carbopheuoxyethylcnesulfonic acid CHz=C-B03H OOCaHa 1-carbocrotyioxyethylenesulfonlc acid CHn=C-S0:H

l-acetylethylenesulfonic acid CH1=C-SOaH O CH:

1-naphthoylethylenesultonic acid CH1: CSO;H

1-crotonylethyienesulfonic acid CH1: C-S 0,11

0 CH=CHOH1 l-amoxyethylenesulfonic acid OH:=CS0:H

l-biphenylyloxyethylenesulfonic acid CH:=CS0:E

ccHiCs a 1-a1lyloxyethylenesultonic acid CH1=CSO;H

CHr-CH=CH:

l-acetoxyethylenesulfonlc acid CH|= 0-S0aH 0' O CH:

1-benzoxyethylenesulfonic acid CH1: C-SOdI C 0 Colin l-acrylyloxyethylenesulfonic acid CHI: C-SOaH O O CH=CH2 z-propenesulfonic acid CH|=CHGH:SO:H

3-butenesultonic acid CH|=CH CHaCHa-S Oa fi-hexenesulfonic acid CH|=CH(CH:) 4-S0aH 2,5-l1exadienesulfonic acid CHa=CHCHaCH=CH CH:BO|H

Sulfonic acids containing more than a, single acid radical, sulfonic or otherwise, may also be used in the preparation of my new copolymertype cation exchange resins, i. e..

l-sulfoethylenesulfonic acid CHFCH-CH-CHROHISOSH 3-sulfo-4-pcntenesulfonic acid 3-vinyl-5-sulfobenzoic acid H 0 8-- S 01H CH=CH$ 2-viny1-1,dbenzenedisultonic acid C H=CH| H|S 03H 2-viny13-suifophenyimethanesulfonic acid 0 O OH CH=CHI C as 01H 3-vinyl4-suliomethyibenzolc acid Sulfonic acids containing more than one CH2=C group may also be copolymerized with polyunsaturated materials according to the process of the present invention.

OaH 1,3-butadiene-2-sulfom'c acid (or 2-sulfo-1,3-butadiene) SOsH 1,4-pentadiene-3-su1fonic acid or 3-suifo-L4-pentadiene) SOIH SOIH 1,4'pentadiene-2,4-disulfonlc acid :11 0 0H 2-sulfo-4-carboxy-1,4-pentadiene SOIH H=CH2 2,4-divinylbenzenesulfonic acid H=CH1 3,fi-divlnylbenzenesulfonic acid CH=CH8 CHzS 0:11

H=CH1 2,5-divinyl-4-carboxyphenylmethanesulfonic acid are therefore suitable.

Instead of the sulfonic acids of the type disclosed as suitable for use in the present invention, derivatives thereof which are hydrolyzable to the acids may be copolymerized with a polyunsaturated material, and the copolymer then hydrolyzed in order to provide free sulionic acid groups for the cation exchange resin. Alkali metal salts of the sulfonic acids may be used; it has already been pointed out that aromatic sulfonic acids are preferably used in the form of their alkali metal salts. Similarly operative are the sulfonic acid chlorides, anhydrides, amides, and alkyl, aryl, and aralkyl esters. Taking ethylenesulfonic acid as a typical example of a sulfonic acid adapted for use in the present invention, I may therefore substitute for it ethylenesulfonyl chloride, CH2=CHSO2C1; ethylenesulfonic anhydride, (CH2=CHSO2) 2O; ethylenesuifonamide, CH2=CHSO2NH2; sodium or potassium ethylenesulfonate; alkyl esters of ethylenesulfonic acid such as methyl ethylenesulfonate, ethyl ethylenesulfonate, isobutyl ethylenesulfonate, amyl ethylenesulfonate, etc.; aryl esters of ethylenesulfonic acid such as Phenyl ethylenesulfonate, naphthyl ethyienesulfonate, etc.; aralky esters of ethylenesulfonic acid such as benzyl ethylenesulfonate; substituted ethylenesulfonamides of the formula 1 CHz-CH-SOaN in which R1 may be hydrogen, alkyl, aryl, or aralkyl, and R2 may be alkyl, aryl, or aralkyl, examples of such amides being N-methylethylenesulfonamide, N,N-diethylethylenesulfonamide, N- methyl-N-ethylethylenesulfonamide, N phenylethylenesulfonamide, N,N-diphenylethylenesulfonamide, N-methyl-N-phenylethylenesulionamide, N-benzylethylenesulfonamide, N-ethyl-N- benzylethylenesulfonamide, and the like. Similar derivatives of other organic sulfonic acids than the ethylenesulfonic acid may also be used. Moreover, it is obvious that mixtures of any numher of sulfonic acids or hydrolyzable derivatives thereof may be copolymerized with a polyunsaturated material in accordance with the present invention.

If a hydrolyzable derivative of a suitable sulfcnic acid is used in the preparation of my new resins, the resinous product obtained may be readil hydrolyzed to the free acid. In general, this is done in the case of the acid chlorides and anhydrides by boiling with water; in the case of the esters, by boiling with alkali; and in the case of the amides, by boiling with acid.

The present invention is in no sense limited to the use of N,N'-methylenediacrylamide as one 01' principal resin-forming ingredients, and any of the diacrylamides disposed in the copending Lundberg application referred to above may be substituted therefor, These diacrylamides may be represented by the following general formula:

a where is that portion of a saturated or unsaturated aliphatic aldehyde, an aromatic aldehyde or a heterocyclic aldehyde which is attached to the carboxylic oxygen, and R is either hydrogen or a hydrocarbon radical, i. e., alkyl, aryl, or aralkyl. Specifically may be mentioned:

NHCO =CH:

HOOC=CH:

Ha N,N'-methylenedimethacrylamide NH 0 o CH=CH1 CHaC NHCO OH=CH| N,N' ethylidenediacrylamide NHCOCH=CHD CHaCH=CHC HGOCH=CHa N,N'-crotylidenediacrylamide on. NHo0d=0H1 NH O O C=CHa a N,N'-benzylidenedimethacrylamide CHCH NBC 0 CH=GH1 ("3H 0 N NHCO GH=OHI N,N"furfurylidenediacrylamide CnHu NH O 0 (i=CH:

NH O O C=CH2 o a N,N-methylenediphenacrylamide cmctm NBC =GH| NH O 0 C= CH:

HICIHI N,N'-methylenedibenzacrylamide and the like.

Similar compounds of the formula wherein X is an alkylene or arylene radical and R is hydrogen or an alkyl, aryl or aralkyl radical may be used, as may be corresponding sulfonamide derivatives of the formula in which Z is alkylene or arylene or that portion of a saturated or unsaturated aliphatic aldehyde, an aromatic aldehyde or a heterocyclic aldehyde which is attached to the carboxylic oxygen, and R is either hydrogen or a hydrocarbon radical as in the foregoing formulae. Thus, specifically, I may use:

NHCOCH=CH2 NH O 0 C H= CH: l,2-diacrylamidobenzeme a Ha Hr-NH C O C: C H:

1,3-dimethacrylamid opropane CH1 CuHu CHr-NH C O C=CH2 Ha-NH C O C=CHn HzCgCs 1,2-dibenzacrylamidoethane CQHE NH 0 0 J= C H:

CtHi

N HC 0 J=CHz 1,3-dlplienacrylamidobenzene NHSO1CH=CHI NHSO|CH=OHz diethylenesulfonamidomethane NHSOzCH=CH2 1,2-diethylenesulionamidobenzene CH: CHPNHSOK J=CHs Hr-NHSO|C=CHI Hi 1,2-dl alpha-methylethylenesulfonamido -ethylene NHS 0: OH=CH2 II CH /(C\ O NHSOzCH=CHz N ,N-urfurylidenediethylenesulfonamide and the like.

Moreover, any polymerizable material containing more than one ethylenic-type double bond but no conjugated aliphatic carbon-to-carbon double bonds may be substituted for the diacrylamides and disulfonamides described above. I prefer those materials which contain a plurality of CH2=C groups as the ethylenic linkages, but the invention is not so limited. Examples of suitable polyunsaturated materials include divinyl ether, divinyl sulfone, allyl ethers of polyhydric compounds such as glycerol, pentaerythritol, resorcinol, etc., divinylbenzene, divinylketone, divin ylsulflde, polydienes, such as polybutadiene, polychloroprene, polyisoprene, etc., polyfumaramide, allyl acrylate, and the like. Pclyesters of allyl alcohol, Z-methallyl alcohol, 2-chloroallyl alcohol, etc., with polybasic acids, both organic and inorganic, may also be copolymerized with unsaturated sulfonic acids according to the present invention. For example, diallyl maleate, diallyl fumarate, diallyl phthalate, diallyl succinate, diallyl carbonate, diallyl malonate, diallyl oxalate, diallyl adipate, diallyl sebacate, diallyl tartrate, diallyl silicone, diallyl silicate, triallyl tricarballylate, triallyl aconltate, triallyl citrate, triallyl phosphate, and the corresponding substituted allyl alcohol esters, are suitable.

It is essential that the material to be copolymerized with an unsaturated sulfonic acid according to the process of the present invention be polyunsaturated, i. e., contain a plurality of ethylenic double bonds, preferably CH2=C groups, and have no conjugated aliphatic carbon-tocarbon double bonds. Thus, while the material must have at least two ethylenic double bonds, it may have three, four, six, eighteen, one hundred, or an infinite number of such linkages.

Similar resins to those of the present invention may be obtained by polymerization of a single compound which combines the essential characteristics of the two principal components of the copolymers described above. For example, polymerization of polybutadiene sulfonic acids, alkali metal salts of divinylbenzene sulfonic acids, allyl ethers of sulfonated phenolic compounds and the like produces resins which may be used in ion exchange processes.

The copolymerization reaction which results in the production of the new cation exchange resins of the present invention is preferably carried out in the presence of a polymerization catalyst. Suitable catalysts include hydrogen peroxide; the acidic peroxides as, for example, benzoyl peroxide, phthalic peroxide, succinic peroxide, and benzoyl acetic peroxide; fatty acid peroxides as, for example, cocoanut oil acid peroxides, lauric peroxide, stearic peroxide, and oleic peroxide; alcohol peroxides as, for example, tert. butyl hydroperoxide, ditert. butyl peroxide; terpene oxides as, for example, ascaridole; and the like. Other polymerization catalysts which may be used include alkali metal persulfates, azo compounds as, for example, alpha,alpha'-azoisobutyronitrile (Porophor N), soluble cobalt salts, i. e., cobalt linoleate and cobalt naphthenate, p-toluene sulionic acid, p-toluene sulfonamide, aluminum chloride, stannic chloride, boron trifluoride, etc. The term "polymerization catalyst" as used is not intended to cover oxygen contained in the resin as an impurity.

The concentration of catalyst employed is usually small and generally ranges from about 1 part catalyst per 1000 yarts of copolymerizable mixture to about 2 parts catalyst per 100 parts of the copolymerizable mixture. If an inhibitor be present, however, up to 5% or more of the catalyst may be necessary.

Choice of a catalyst in any particular case depends upon the desired result. For example, the peroxide catalysts are generally preferred and they accelerate copolymerization across the double bonds of the copolymerizable materials. If, however, one or both of the copolymerizable materials is an aromatic compound and an acid catalyst such as, for example, aluminum chloride, boron trifluoride or the like is selected, some or all of the copolymerization may take place by alkylation of the aromatic nucleus. This alkylation-type polymerization is generally to be avoided, if possible, in the present invention, but if it does take place to some extent it need not adversely affect the utility of my new products for ion exchange operations.

It is sometimes advisable to incorporate in the copolymerizable mixture of the present invention a small proportion of a polymerization inhibitor in order to avoid polymerization thereof on storage. When polymerization is desired, enough catalyst is added to overcome the effect of the inhibitor and to promote the reaction.

Suitable polymerization inhibitors for this reaction include phenolic compounds, especially the polyhydric phenols, aromatic amines, aldehydes, sulfur compounds, and the like. Examples of some inhibitors are hydroquinone, benzaldehyde, ascorbic acid, isoascorbic acid, resorcinol, tert. butyl catechol, tannin, sym. di-beta-naphthyl-p-phenylenediamine, phenolic resins, etc.

The concentration of inhibitor is preferably low, and I have found that less than about 1% is usually sufiicient. With the preferred inhibitors, I need use only about 0.01% to about 0.1%.

Some substances which normally exhibit an inhibiting effect on polymerization may, under certain circumstances, promote polymerization. Since an oxidation-reduction system is apparently involved in such cases of polymerization and the peroxide type of catalyst is generally preferred for the preparation of my cation active resins, I find the Redox peroxide-bisulfite system particularly useful.

Polymerization may be eifected by means of heat, light, or a combination of the two. Ultraviolet light is more effective in this respect than ordinary light. In general, polymerization temperatures will range from about 20 to 25 C. up to the boiling point of the lower boiling of the two copolymerizable ingredients.

The unsaturated organic sulfonic acids and polyunsaturated materials are generally combined in molar ratios of from about 1:1 to about 20:1, unsaturated sulfonic acid to polyunsaturated compound, although the invention is in no sense limited to these particular proportions.

The copolymerization reaction resulting in the production of my new cation exchange resins may be carried out in aqueous solution or in solution in a suitable polar organic solvent such as, for example, dioxane; aliphatic monohydric alcohols including methanol, propanol, etc.; glycols, i. e., ethylene glycol, diethylene glycol, 2- methyi-2,4-pentanediol, propylene glycol, etc.; aliphatic ketones including dimethyl ketone, methyl ethyl ketone, etc. Generally speaking, any polar organic solvent which is stable in the presence of acid is suitable.

Copolymerization of the organic sulfonic acid and polyunsaturated material may also be carried out, if desired, in emulsion 0r dispersion in an aqueous or non-aqueous medium. In this case, cationic, anionic, or non-ionic surface active agents may be added.

The resins prepared according to the present invention may be cured at from about room temperature (20-"5 C.) to about 150 C. I prefer heating at elevated temperatures, i. e., from -l50 C.

It is an advantage of the present invention that the granular water-insoluble synthetic resins produced in accordance therewith are capable of exchanging cations in liquid media and of removing cations from liquid media. In this connection, my resinous materials may be used in admixture with other cation active materials or with inert materials, or they may be used alone. For example, my resins may be applied before gelation to a suitable carrier such as diatomaceous earth, clay, charcoal, etc.

Resinous materials prepared according to my invention are useful in the removal of cations from fluid media, especially from aqueous solutions. The resins may be used in the hydrogenactivated form to remove cations from solutions of bases and salts, and they may also be employed as exchange materials in accordance with the principles applied to the use of the natural and synthetic zeolites. Thus, the resin may be activated with a sodium salt such as sodium chloride, and upon contact with a solution containing calcium, magnesium, or other cations, an exchange of the latter ions for the sodium ions takes place.

The activating solutions or regenerating solutions for my resins are dilute acid solutions or dilute salt solutions, e. e., about 0.2%20% of sulfuric acid, hydrochloric acid, sodium chloride, potassium chloride, etc.

To be sufiiciently insoluble for practical use in the art of water purification, a resin should have a sufficiently low solubility that it will not be dissolved away rapidly by the solution to be treated. Thus, water should not dissolve more than 1 part of resin in 1000 parts of water and preferably should not dissolve more than 1 part of resin in 100,000 parts of water when passed through a bed of resin (after the first cycle comprising an activation, exhaustion, and reactivation of the resin).

It is preferable to grind and screen the resins to a particle size of from about 8-60 mesh. Use 01' larger particles causes channeling, and smaller particles of resin have been found to pack, thus reducing the cation exchange efliciency oi' the material.

My resinous materials are useful for a wide variety of purposes. Some of the uses which may be mentioned by way of example are: water purification; purification of glycerol, glycols, etc.; purification of aqueous solutions containing sugar, including sugar cane juice, sugar beet Juice, sugar syrups, etc.; purification of water from lead pipes; removal or heavy metal ions from food, beverages, and pharmaceutical products; decolorization of solutions containing coloring matters, etc. My resins may also be employed to recover valuable metal cations from dilute solutions, e. g., gold trom sea water, chromium from chrome tanning liquors, silver from photographic baths, etc. Another important application of my materials is in the absorption or adsorption of gases such as ammonia, the amines, e. g., triethyl amine, methyl amine, etc., from fluid media, either dissolved in a liquid or from vapors. The resins may also be employed as catalysts for many of those reactions normally involving the use of acidic catalysts such as the inversion of sucrose, the conversion of starches to sugars, etc.

I claim.

1. A granular, water-insoluble cation exchange resin active for the removal of cations from solution which is a copolymer of (1) ethylenesulfonic acid and (2) N,N-methy1enediacrylamide, the

molar ratio of (1) to (2) being from about 1:1 to about 20:1.

2. The process which comprises passing an aqueous solution containing cations through a bed of the resin of claim 1.

3. A process for preparing a granular waterinsoluble cation exchange resin active for the removal of cations from solution which comprises heating a mixture including (1) ethylene suli'onic acid and (2) N,N'-methylene diacrylamide in a molar ratio of from about 1:1 to about 20:1 in the presence of a polymerization catalyst, curing the resulting gel by heating, and granulating the cured gel.

JAMES R. DUDLEY.

REFERENCES crran The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,348,705 Alderman May 16, 1944 2,366,007 DAlelio Dec. 26, 1944 2,427,640 Whitehill Sept. 16, 1947 2,469,472 Nachod May 10, 1949 2,475,846 Lundberg July 12, 1949 FOREIGN PATENTS Number Country Date 67,658 Norway Apr. 3, 1944 

1. A GRANULAR, WATER-INSOLUBLE CATION EXCHANGE RESIN ACTIVE FOR THE REMOVAL OF CATIONS FROM SOLUTION WHICH IS A COPOLYMER OF (1) ETHYLENSULFONIC ACID AND (2) N,N''-METHYLENEDIACRYLAMIDE, THE MOLAR RATIO OF (1) TO (2) BEING FROM ABOUT 1:$ TO ABOUAT 20:1. 